WPF的Expander是显示内容视图控件，扩展区域的内容可以展开或折叠。ExpandDirection是设置扩展方向，FontSize设置字体大小，IsExpanded展示显示。在Expander中加入ScrollViewer来显示指定的滚动样式。
Demo版下载地址：
https://download.csdn.net/download/liaohaiyin/63234875
Newbeecoder.UI控件库根据用户需求开发稳定而高效项目，通过视频来演示控件库整体功能：
视频内容
在Newbeecoder.UI控件库用NbExpander显示折叠菜单样式：
NbExpander案例代码：
<NbExpander Header="推荐" Style="{StaticResource DefaultExpanderStyle}" IsExpanded="True">
<StackPanel Margin="30,0,0,0">
<StackPanel Orientation="Horizontal" Height="20" VerticalAlignment="Center">
<NbIcon CornerRadius="2" Width="12" Height="12" Data="{DynamicResource Icon-App-Fill}"/>
<TextBlock Margin="3,0,0,0" Text="发现音乐"/>
</StackPanel>
<StackPanel Orientation="Horizontal" Height="20" VerticalAlignment="Center">
<NbIcon CornerRadius="2" Width="12" Height="12" Data="{DynamicResource Icon-Copy-Fill}"/>
<TextBlock Margin="3,0,0,0" Text="私人FM"/>
</StackPanel>
<StackPanel Orientation="Horizontal" Height="20" VerticalAlignment="Center">
<NbIcon CornerRadius="2" Width="12" Height="12" Data="{DynamicResource Icon-Home-Fill}"/>
<TextBlock Margin="3,0,0,0" Text="热榜歌曲"/>
</StackPanel>
<StackPanel Orientation="Horizontal" Height="20" VerticalAlignment="Center">
<NbIcon CornerRadius="2" Width="12" Height="12" Data="{DynamicResource Icon-User-Fill}"/>
<TextBlock Margin="3,0,0,0" Text="经典歌曲"/>
</StackPanel>
</StackPanel>
</NbExpander>
<NbExpander Header="收藏的歌单" IsExpanded="True" Style="{StaticResource DefaultNoExpanderStyle}">
<StackPanel Margin="30,0,0,0">
<StackPanel Orientation="Horizontal" Height="20" VerticalAlignment="Center">
<NbIcon CornerRadius="2" Width="12" Height="12" Data="{DynamicResource Icon-App-Fill}"/>
<TextBlock Margin="3,0,0,0" Text="发现音乐"/>
</StackPanel>
